Though it is quite evident that fiber optic transmission systems are the "wave of the future" with respect to voice and data communications, present day communications must still deal with electrical conductors, since these comprise the majority of the communications highway. Of course, the problem with electrical conductors is their limited bandwidth capabilities. Because the need for fast and reliable information is an ever increasing commodity, communications lines are increasingly required to carry more and more information, i.e., the required data rates are ever increasing. Fiber optic cables are well adapted for these high data rates; however, the existing physical plants of essentially copper wires is not up to the task. This dilemma is made ever more burdensome by the fact that replacement of electrical conductors with fiber optic cables is both laborious and expensive, while also requiring replacement of the associated transmitting and receiving terminal devices.
In response to the aforementioned problems, several prior solutions have focused on transmitting data at FDDI (fiber distributed-data interface) and ATM (asynchronous transfer mode) data rates on existing media such as shielded twisted pair. This emphasis has been on coding schemes that reduce the signal bandwidth to meet FCC emissions requirements. Such schemes include QPRIV-IV (please refer to Quaternary Partial-Response Class-IV Systems for 125 Mbit/s Data Transmission Over Unshielded Twisted-Pair Cables, G. Cherubini, S. Olcer, G. Ungerboeck, Proceedings of the IEEE International Conference on Communications 1993, p. 1814-1819) and CAP-32 (please refer to Bandwidth-Efficient Digital Transmission up to 155 Mb/s Over Unshielded Twisted-Pair Wiring", Gi-Hong Im, J. J. Werner, Proceedings of the IEEE International Conference on Communications 1993, p. 1797-1803), which meet the technical criteria of reducing the bandwidth of the high-speed data signals and maintaining a good link error rate performance, but are costly and require complex circuitry (e.g., very large scale integration ("VLSI") circuitry) in their implementation.
Accordingly, there is a need in the art for a less expensive and simpler system and method for decreasing the amount of bandwidth required to transmit high bandwidth signals over electrically conducting transmission lines.